Well, that's a rather complex question and it's phrased in such a way that anybody could make a slippery response and think they got away with it. But basically the brain sees the light where the eyeball is just an external component of said brain.

"I don't envision a single thing that, when developed & cultivated, leads to such great benefit as the mind. The mind, when developed & cultivated, leads to great benefit."

"I don't envision a single thing that, when undeveloped & uncultivated, brings about such suffering & stress as the mind. The mind, when undeveloped & uncultivated, brings about suffering & stress."

Based on this sutta, and others we can say: there is nothing that sees. There is just seeing of a ray of light (because of some prerequisite conditions). Maybe we can say "seeing sees" but even that is not the most accurate way of describing what really is.

SamKR wrote:Based on this sutta, and others we can say: there is nothing that sees. There is just seeing of a ray of light (because of some prerequisite conditions).

That's about the best answer so far, IMO. It could be extended to incorporate points others have mentioned, e.g. the perception of a ray of light arises in the brain because of the effect of light reaching the eye and stimulating nerves there, but perception does not imply a perceiver. Or something like that.

SamKR wrote:Maybe we can say "seeing sees" but even that is not the most accurate way of describing what really is.

Not so good, since "seeing sees" is grammatically problematic enough to be meaningless.